Abstract

The electromagnetic transmission, reflection, and absorption characteristics of two-dimensional metallic photonic crystals with a coherent atomic gas as the host medium were systematically studied, with emphasis on the appearance and features of mini passbands within bandgaps of the unfilled (gas-free) crystals. Only normally incident s-polarized plane waves were considered. The mini passbands are connected with strong frequency dispersion of the relative permittivity of the host gas, being highly variable for a certain narrow regime of frequencies. Transmission effects similar to those connected with defect modes can appear in photonic crystals, which are associated with localization of dispersion in the frequency domain rather than with spatial localization of the field at structural defects. In addition, analogy with Fabry–Perot resonances is possible within the new bands. Their locations can be strongly sensitive to a variation of gas parameters so that they can be efficiently tuned at fixed frequency. Also, the occurrence of high-absorbance bands can be correlated with the frequency-dependent properties of the metal and the coherent atomic gas. Finally, the energy of the incident wave can be distributed in a desired proportion between either transmittance or reflectance on one hand and absorbance on the other.

Figures (15)

Schematic of the boundary-value problem considered here. An s-polarized plane wave is normally incident on a 2D PC comprising parallel rods of infinite length, which are immersed in a CAG confined to the region 0<y<D.

Spectra of T (black solid line), R (red dashed line), and A (blue dotted line) for a PC made of metallic rods. Whereas P=8, d/a=0.4, ωp=4.34π×1015s−1, and γ/ωp=0.01, the CAG properties are the same as in Fig. 2; ω1a/c=4.7. New mini passbands are denoted by “1” and “2,” and the asterisks denote the high-absorbance bands with A≈1.

Dependence of T on Ωca/c for three values of ka:4.30001 (blue solid line) which is the same as in Fig. 8, ka=4.2996 (red dashed line), ka=4.2994 (green dashed-dotted line), and ka=4.2998 (black dotted line). All other parameters are the same as in Fig. 8. T≈0 at ka=4.2998.

Dependence of A on Ωca/c for three values of ka:4.30001 (violet solid line) which is the same as in Fig. 8, ka=4.2996 (red dashed line), ka=4.2994 (green dashed-dotted line), and ka=4.2998 (blue dotted line). All other parameters are the same as in Fig. 8.